Apparatus for compensating for incorrect reproduction of color in color photographs



BUSSE' Sept. 3, 1940.

APPARATUS FOR COMPENSATING FOR INCORRECT REPRODUCTION I OF COLOR IN COLOR PHOTOGRAPHS.

Filed Aug. 17, 1959 5 Shets-Sheet 1 F M M M 1 ii.

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' /n venfor Ferd/hand Buss By his Affo rneys M;

' Sept. 3, 1940. I F B SSE 2,213,382

APPARATUS FOR COMPENSAT ING FOR INCORRECT REPRODUCTION OF COLOR IN COLOR PHOTOGRAPHS Filed Aug. 17, 1939 5 Sheets-Sheet 2 {I lim Jib BIDDER 2b In van for By his Afforneys Sept. 3, 1940. uss 2,213,382 APPARATUS FOR COMPENS-ATING FOR INCORRECT REPRQDUCT OF COLOR INCOLOR PHOTOGRAPHS ION Filed Aug. 17, 1959 3 Sheets-Sheet 3 fig? 3a y g 9 3a a I Jib Inkehfor FrdinnBss By his Aflorhey; I

Patented Sept. 3, 1940 UNITED STATES PATENT OFFICE APPARATUS FOR COMPENSATING FOR IN- CORRECT REPRODUCTION OF COLOR I COLOR PHOTOGRAPHS Ferdinand Busse, Munich, Germany, assignor, by mesne assignments, to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application August 1'7, 1939, Serial No. 290,590

In Germany August 22, 1938 My present invention relates to improvements in compensating for incorrect reproduction of color.

It is often experienced in color photography that the color tones of the finished picture are not a correct reproduction of those of the object photographed. Such incorrect rendering of color may be due for instance to the conditions of illumination or to an incorrectly chosen time of exposure. In this case the photographs show an excess of one or another color.

In order to remove the errors in the reproduction it has'already been proposed to rectify the color value during copying. It is, for example, known in copying from lenticular films to remove during reproduction the errors in the colors by controllingdiaphragms in, front of the several color filters with the aid of a color tri-.

angle. Such control is efiected by a device dis- 30 placeable in two dimensions and necessitates a complex electric circuit with the use of electric relays.

.It isan object of my invention to provide a simple apparatus for compensating for reproductions of color during copying or enlarging color photographs. I i

Another object of the invention is to provide in the path of the copying light a filter which has uncolored fields and fields colored in the primary colors, the area of each of the colored fields being equal to one another and in'their sum equal to the total uncolored area.

Further objects of my invention will appear from the detailed description iollowing'herein- 55 after.

The filter is combined with means which enable the copying light to pass through selected fields or combinations of fields. The fields colored in the primary colors may be arranged in vertical strips which alternate with parallel uncolored strips of equal width. The Juncolored fields may .be transparent or they'may consist of a grey filter or a grating screen, the blackeningof the grey filters or the density of the grating 5 screens preferably being such that the absorption of light thereby is equal to the absorption of light by the colored fields.

In order to enable the copying light to pass through selected fields or combinations of fields; that is: in order to .cover the unwanted fields of the filter, there may be arranged over the latter an apertured' screen which can be displaced parallel tothe filter in a system of coordinates corresponding with the arrangement of the colored and uncolored fields. This screen has 11- Claiins. (Cl. -73) shows the colored component selected and the other serves for the adjustment of the uncolored light which is to be combined with the colored light. The scale for selectlngthe combination of colors ha's subdivided adjacent fields of equal size colored in the primary colors, the percentage of which can be read off by means of a double pointer connected I with the knob. The uncolored transmittedlight .is' adjusted by a pointer connected with the other knob.

v The invention is illustrated by way of example in the accompanying drawings, in whichv Fig. 1 is a view of'the filter,

Fig. 2 is a view of perforated screen for partly covering the filter. I

Fig. 3 is a view of the filter with the screen superimposed. i

Fig. 4 is a section through copying apparatus in which the filter and screen have been inserted.

Fig. 5 is a view of apparatus for controlling the I screen. I Y I Fig. 6 is a side view of the "control apparatus shown in Fig. 5, and. r

Fig. 7 is a view of the copying apparatus shown in Fig. 4.

The screen I shown in Fig. 1 has vertical strips 'of equal breadthi' the strips being alternately.

colorless and composed of colored fields. The colored fields which are arranged one below the larlyrecurring order in the primary colors @red (Ir), blue (lb) and-green (lg). The uncolored strips lw are white, they may, however, be transparent pf may consist of grey filters or grating screens, the blackening of the grey filters or the density of the gratingscreens preferably being such that the absorption-of light thereby isjequal to the absorption of light by the colored fields. By such an arrangement of colored and uncolored fields itis possible with theaid of amask, for example apertured screen .2 (see Fig.- 2), to alter the light falling, on the negative, for the The'screen is moved by I other and are ofequal size are colored in regu red, green or blue. The apertured screen 2 for covering the unWantedcombinati-ons of colors has apertures 2a which in respect of their number, shape and size correspond with the colored fields and are so arranged that they are separated horizontally by the length of one colored field and vertically by the height of two colored fields. v

If such a screen 2 is superimposed on the color filter I any desired part of a colored or uncolored field can be freed for the passage of the copying light by displacing the screen 2 parallel .to the filter I in the directions of a .pair of rectangular coordinates.

Such a displacement of the screen 2 in relation to the filter I is illustrated in Fig. 3. By the displacement of the screen 2 in the directions of the arrows A and B only the parts of the fields Ir, Ib and Iw shown behind the apertures remain open for the passage of the, copying light. From Fig. 3 it can be seen that the proportion; of white light and light of the primary colors can be varied in any desired manner by further displacement of the screen 2. v

The arrangement of the filter "I and screen 2 in a copying apparatus can be seen from Fig. 4 in which 3 denotes the housing of the apparatus, 4 the source of light, 5 and 6 a reflector for the source 4, I a diffusing screen, 8- the copying material and 9 the pressure plate The pressure plate is mounted on a shaft 9a which turns in bearings 3a and is actuated by alever 9b (see Fig. 7) Between the diffusing screen 1 and the source 'of light 4 is situated the filterl and superimposed screen 2.-

h The apparatus shown in Figs. -5 and 6 enablesthe color necessary for the compensation of a given incorrectness of reproduction to be obtained by controlling the movements of the screen 2 in front of the filter I. The apparatus comprises a base plate on which the screen 2 is arranged so as to be movable in the directions of a pair of rectangular coordinates, theiscreen being carried in 'a movable frame 'I I. The frame I I has at its upper and. lower ends lugs I Ia whichv engage by means of pins III) in slot guides 2b in the screen 2. The frame II is moved 'to and fro by two crooked levers I 2 which pivot on fulcra I3 on the base plate I and are connected with the frame II by pins and slotsll2a. The, crooked levers I2 are driven by a rod II which has a fork-shaped lug I la (see Fig. 6) in which a pin Ia of the pointer arm I5 engages. The pointer arm I5 is mounted on an axle I6 which isconnected with the small knob II. By turning the yknob I! the rod I4 is displaced and the displacement is transmitted to the levers l2'by .pin and slot connections I2b.. For the movement of the screen 2 on the frame II in the direction of the ordinates, the screen is provided with a pin which is engaged by a slot Illa in a lever I8. The fulcrum I9 of the lever I8 is fixed to the base plate I 0 and the lever is moved 'by a rack- 20 which is driven by v a toothed wheel 22 mounted, on a hollow shaft 2|. On the other end of the shaft 2| is mounted thelargeknob 23-. 1

Round the shafts I6v and 2I is a housing 24 on which two neighbouring translucent scales 25 and 26 are marked. The scale 25 consists of the, copying or enlarging of color photographs,

coloredfields ,ofequal size which are arranged from above to below in the order red, blue, green, red, thatis in the same order as the colored fields of the filter. On the shaft 2| is fixed a double pointer 21 of which the ends 21a traverse the scale 25 at a distance apart of one colored field of the scale. The scale 26 indicates the displacement of the screen 2 over the uncolored fields Iw. It is advantageous to express the extent to which the uncolored fields are free as a percentage of uncolored light. Forthlspurpose the percentage of uncolored light is'read ofi the scale 26 by means of the end lib of the pointer I5 which isfixed on the shaft I6.

The apparatus work in the following manner.

I If, for example, a test has shown'that to compensate for an incorrect rendering of color itis on the blue field of the scale 25, and to turn the finger I5b foradjusting the white light to the appropriate percentage number on the scale 26. The screen 2 then occupies approximately the position shown in Fig. 3. In exactly the same manner the screen 2-can'be adjusted to free the field's of a single color or the uncolored fields. If the absorptivity of the uncolored fields (grey filter) is made equal to that of the individual colored fields, the absorption of light by the filter remains the same independently of which field or combination of fields is freed by the screen. This has the advantage that the quantity of light falling on the copying material is always the same, so that alteration of the exposure time when compensation for incorrect color is not necessary.

I claim: I

1. In an apparatus for compensating, during the copying or enlarging of color photographs, for incorrect reproduction 'of color in said photo-1 graphs, in combination, a filter provided with uncolored fields; and fields colored in the primary colors, the area of each of said colored fields being equal to oneanotherand in their sum equal to the total area of said uncolored fields, and. means for enabling the copying-light to through selected fields of said filter.

/ I 2. In an apparatus for compensating, during the copying or enlarging of color photographs, for incorrect reproduction of colorin said photographs, in combination, a filter provided with un-- colored fields and fields colored in the'primary' 1 Icolors, said uncolored and colored field being so arranged that rows of said uncolored fields alternate with rows of said colored fields, the area'of each of said colored fields being equal to one another and in-their sum equal to the total area of 'saidun'colored fields, and means for enabling the copying light to passthrough selected fields of said filter.

3. In an apparatus for compensating, .during the'copying'or enlarging of color photographs,

for incorrect reproduction of color in said photographs, in combination, a filter provided with transparent uncolored fields and fields colored in the primary colors, the area of each of said colored fields being equal to one another and in their 1 sum equal to the total area of said uncolored fields, and means for enabling the copying light to pass through selected fields of said filter.

4. In anapparatus for compensating, during for incorrect reproduction of color in said photographs, in combination, a filter provided with grey-colored fields and fields colored in the p111 fields, and means for enabling the copying light to pass through selected fields of said filter.

5. In an apparatus for ,compensating, during the copying or enlarging of color photographs, for. incorrect reproduction of color in said photo-' graphs, in combination, a filterprovided with uncolored'fields consisting of grating screens and fields colored in the primaryjcolors, the area of each ofsaid colored fields being equal to one another and in their sum equal to the total area '01 said uncolored fields, and means for enabling the copying light to pass through selected fields of said filter.

6. In an apparatus for compensating, during the copying or enlargingof colorphotographs, for incorrect reproduction of color in said photographs, in combination, a filter provided with grey-colored fields and fields colored in the primary colors, the area of each of said colored fields being equal to one another and in their sum equal to the total area of said grey-colored fields; the blackening of said grey-colored fields being such that the absorption 'of light thereby-is equal to the absorption o'f'light by said coloredfields, and means for enabling the copying light to pass through selected fields of said filter.

7. In an apparatus for compensating, during the copying or enlargingof color photographs, for incorrect reproduction of color insaid photographs, in combination, a'filte'r provided with uncolored fields consisting of grating screens and fields colored in the primary colors, the area of. each of said colored fields being equal to-one another and in their sum equalto the total'area of said uncolored fields, the density of said grating screens being such that the absorption of, light thereby is equal to the absorption light colored fields and fields colored in the primary colors, the area of each of said colored fields being equal to one another and in their sum equal to the total area of said uncolored fields, and an apertured screen .arranged'oversaid filter and adapted to be displaced parallel to 'saidfilter in the directions of a pair of coordinates correspond-l ing with the arrangement of the fields.

9. In an apparatus for compensating, during the copying or enlarging of color photographs, for

pass through selected fields incorrect reproduction of color in said photographs, in combination, a'filte'r provided withuncolored fields and fields colored in the primary colors, the area of each of said colored fields being equal to one 'anotherandin their sum equal to the total area of said uncolored fields, an I apertured screen arranged over said filter, two adjacent coaxial rotatable knobs adapted to displace said screen parallel to'said filter'in the directions'of apair of coordinates corresponding 0 with the arrangement of the fields, and a combination of toothed wheel, rack and crooked lever for transmitting therotation of said knobs to said screen.

10. In an apparatus for compensating, during the copying or enlarging of color photographs, for incorrect reproduction of color in said photographs, in combination, a filter provided withuncolored fields and fields colored in the primary" colors, the area of each or said colored fields being equal to one another and in their sum equal to the total area of said uncolored fields, an apertured screen arranged over said filter, two adjacent coaxial rotatable knobs adapted to dis,- place said screen parallel to said filter in the directions of a pair of coordinatescorrespondingwith the arrangement of the fields, two adjacent scales arranged concentric with said knobs, one of said scales servingior the quantitative selec-.- tion of uncolored fields and the other scale for the quantativeselection of colored fields, and a I ,combination of toothed wheel, rack and crooked lever for transmitting the rotation of. said knobs.

to said screen. D 11. In an apparatus for compensating, during the copying or enlarging of color photographs, for incorrect reproduction of color in said photographs, in combination a filter provided with uncolored fields and fields colored in the primary colors, the area of each of said colored fields be- 40 H ing equal to one anotherand in' their sum equal 3.

to the total area of said uncolored fields, an apertured 801 18811, arranged over said filter,, two\ 1 adjacent coaxial rotatable knobs adapted'to. dis-- place said screen .parallel to said filter-in the directions of a pair of coordinates corresponding with the arrangement of the fields, two adjacent I scales arranged concentric with said knobs, one *0! said scales serving for the quantitative selection of uncolored fields andthe other scale for the quantitative selection of vcolored fields, said scale for the selection of colored fields having subdivided adjacent fields of equal size colored v in the primary colors, a 'double' pointer connected 5 with one of said knobs and serving for reading of! the percentage of the primary colors, and acombination of toothed wheel, rack and crooked lever tor transmitting the rotation of said kno to said screen.

FERDINAND BussE. 

